1. Field of the Invention
The invention relates to an electrical connector assembly, particularly to a board-to-board connector assembly which includes a plug connector used to be soldered to a first printed circuit board (PCB) and a receptacle connector used to be soldered to a second PCB. The first and second PCBs are electrically interconnected when the plug connector is inserted into the receptacle connector.
2. The Prior Art
Board-to-board connector assemblies are widely known by those skilled in the art of connector technology and popularly used in laptop computers (portable computers), wherein a board-to-board connector assembly includes a plug and receptacle connector used to be mounted on two separate PCBs, respectively. The two PCBs are electrically interconnected when the plug connector is inserted into the receptacle connector.
U.S. Pat. Nos. 5,057,027 and 5,112,235, Taiwan Patent Nos. 80105936, 81216612 and 83209060, and Japan Patent Nos. 3-173337, 3-359550 and 4-212046 show some board-to-board connector assemblies. These prior art connector assemblies have the common disadvantages as set fort below.
First, none of the contacts in the plug and receptacle connectors have means which can effectively prevent a disengagement between the engaging contacts of two connected connectors when a vibration or shock is exerted thereto.
Second, the gap between the opposite contacts in the receptacle connector is not always kept constant, which may cause the contact force (and therefore the electric resistance) between each pair of the engaging contacts to be different from each other, when the plug connector is inserted into the receptacle connector. Different electric resistance between different engaging contacts means that the transmission of signals between two connected connectors cannot have a good quality. Furthermore, the contacts in the prior art receptacle connectors do not have a preload acting thereon; this way, the contact force between the engaging contacts may not be always large enough to ensure a positive engagement therebetween.
Third, to ensure that the terminal portions of the contacts respectively in the plug and receptacle connectors are spaced from each other a predetermined distance, whereby the terminal portions can be correctly soldered to the PCBS, the prior art connector assemblies need to use spacers in the plug and receptacle connectors to locate the terminal portions of the contacts. Since the spacers are formed individually and then assembled with the housings of the connectors, the spacers additionally increase the cost of the prior art connector assemblies.
Fourth, due to the close fit between an elongated projection in the plug connector and a recess in the receptacle connector for receiving the projection, the projection must be carefully and precisely aligned with the recess to be inserted into the recess so that the two connectors can be connected. Such a precise alignment between the projection and the recess causes the connection of the two connectors to be uneasy and inconvenient. Thus, the connection of the receptacle and plug connectors of the prior art connector assemblies cannot be achieved quickly and efficiently.
Therefore, an objective of the invention is to provide a board-to-board connector assembly including a plug and receptacle connector, wherein a protrusion is formed between the free end and the contact portion of each of the contacts in the plug connector and the contact portion of each of the contacts in the receptacle connector is formed to have an arced configuration. When two connected connectors are going to be separated from each other due to a vibration or shock being exerted thereto, the protrusions will be blocked by the contact portions of the contacts in the receptacle connector to prevent such a separation.
Another objective of the invention is to provide a board-to-board connector assembly including a plug and receptacle connector, wherein the gap of the opposite contacts in the receptacle connector is kept substantially constant, whereby when the plug connector is inserted into the receptacle connector, the contact force between each pair of the engaging contacts is substantially the same. Furthermore, each of the contacts in the receptacle connector is preloaded, whereby when the plug connector is inserted into the receptacle connector, a sufficiently large contact force can be generated between the engaging contacts to ensure a positive engagement therebetween.
A still further objective of the present invention is to provide a board-to-board connector assembly including a receptacle and plug connector, wherein each of the housings of the receptacle and plug connectors is integrally formed with a locating means on a rear side thereof. The locating means is sed to locate the terminal portions of the contacts so that hey can be spaced from each other with a predetermined and usually equal distance.
Yet a still further objective of the present invention is to provide a board-to-board connector assembly including a plug and receptacle connector, wherein the recess of the receptacle connector for receiving the projection in the plug connector has a flared inlet, whereby the projection of the plug connector can be easily inserted into the recess of the receptacle connector to achieve the connection of the two connectors.